8.18 Light emitting diode [LED]

On forward biasing a p-n diode, energy is given off in the form of heat in some diodes, while photons are emitted in addition to heat in some other diodes. A p-n diode specially prepared to produce visible and IR light on forward biasing is called light emitting diode. On forward biasing a LED, the majority carriers present in the respective regions of diode cross the p-n junction. The free electrons at the n-side move towards the p-side and holes at the p-side move towards the n-side of the diode. The free electrons that enter the p-side from the n-side are called minority carriers in the p-region and vice versa.

This increases the local minority carrier population than the normal value. This is known as minority ...

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